CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Statement of Comprehensive Income [Abstract]
Net income	$ 24,786	$ 21,696	$ 45,648	$ 52,612
Unrealized gains and losses:
Unrealized holding gains on available-for-sale securities arising during the period	703	2,236	5,532	11,821
Tax effect	(160)	(584)	(1,459)	(3,061)
Net of tax	543	1,652	4,073	8,760
Reclassification adjustment for realized losses (gains) included in net income		279	(29)	280
Tax effect		(62)	6	(62)
Net of tax		217	(23)	218
Unrealized losses on cash flow hedges	(82)	(49)	(3,397)	(977)
Tax effect	42	27	955	309
Net of tax	(40)	(22)	(2,442)	(668)
Reclassification adjustment for realized losses (gains) included in net income	631	(204)	942	(563)
Tax effect	(196)	46	(265)	125
Net of tax	435	(158)	677	(438)
Unrealized pension plan gains and losses:
Unrealized pension plan losses before reclassifications				(562)
Tax effect				158
Net of tax				(404)
Reclassification adjustment for amortization included in net income	75	90	226	269
Tax effect	(21)	(26)	(63)	(76)
Net of tax	54	64	163	193
Total other comprehensive income	992	1,753	2,448	7,661
Total comprehensive income	$ 25,778	$ 23,449	$ 48,096	$ 60,273